KR100351224B1 - Hybrid generator with perforating pillar - Google Patents

Abstract

The gas generator (1) has a tubular metal body (2) with gas outlets (25) and an inner partition (26) with a central hole (27 covered by a seal (28), dividing the body into combustion and gas pressure chambers. Between the detonator and partition the bod contains a fixed support (30) with a cavity for a solid moving piston (31). The gas generator (1) has a tubular metal body (2) closed at one end by a pyrotechnic detonator (4) and at the other by a m stopper (22). The body has gas outlets (25) and an inner partition (26) with a central hole (27) covered by a seal (28), dividin the body into combustion and gas pressure chambers. Between the detonator and partition the body contains a fixed support (30) w a cavity for a solid moving piston (31) with peripheral fins (45) a pillar (32) which rests against the seal (28). Prior to the generator's operation the support and piston isolate the combustion chamber from the outlets (25).

Description

Hybrid generator with perforating pillar

FIELD OF THE INVENTION The present invention relates to the field of protecting passengers in a vehicle using inflatable air bags. More particularly, the present invention relates to tubular hybrid gas generators for inflating such airbags.

To inflate airbags to protect the passengers of a vehicle, they have previously used a compressed gas reservoir that is opened by a pyrotechnic valve. Thus, U. S. Patent No. 3,690, 695 describes a device for inflating a protective airbag. Such a device consists of a gas reservoir under pressure isolated from the duct leading to the airbag by a hermetic bulkhead on which the fin-shaped solid piston rests.

In the event of a collision, a pyrotechnic primer placed behind the piston moves the piston forward to tear the bulkhead and allow compressed cold gas to enter the duct. When the hot gas from the pyrotechnic charge cannot be mixed with the cold gas, it is heated by passing over a bed of magnesium that reacts with the hot gas. Such devices are produced in a dangerous and complex way in terms of their principle of operation.

Thus, an attempt is made to improve a hybrid gas generator comprising, on the one hand, a pyrotechnic filling which can contain a reservoir of cold gas under pressure and on the other hand can fulfill two functions of heating the gas reservoir and heating the cold gas. Was done.

PCT publication WO 98/09850 describes a piston coupled to a tubular hybrid generator and a pyrotechnic igniter comprising compressed gas. In a collision, the trigger of the igniter moves the piston to open the generator at the opposite end to the pyrotechnic igniter and to heat the low temperature gas by mixing the hot and cold gases supplied by the pyrotechnic igniter inside the generator. Let's do it. When this occurs, an urgent pressure rise is observed inside the generator for obvious safety reasons, and the amount of gas that can be stored in the generator is limited to below the theoretical maximum. As a result, a generator in which the stroke of the piston is guided along the entire length of the generator is relatively expensive to produce.

Thus, in order to simplify the actual production of the generator, a type of tubular hybrid generator with a lateral gas discharge orifice has been proposed, for example in PCT publication WO 98/12078, and the reservoir for compressed cold gas is provided on one side of these orifices. The pyrotechnic chamber is arranged on the other side. The gas reservoir is opened by a hollow piston having a central duct which, after opening, allows the hot gas to enter the reservoir and mix with the cold gas. The heated mixture is then discharged from the reservoir through a gap around the piston resulting from the destruction of the partition used to close the reservoir.

Although this solution yields a tubular hybrid generator that is produced relatively simply in practice, it does not overcome the disadvantage in that the hot gas from the combustion of the pyrotechnic charge enters the inside of the reservoir for the compressed cold gas.

Disadvantages of this kind also appear in solutions using projectiles instead of pistons to open reservoirs, as described, for example, in US Pat. No. 5,464,247.

In particular, tubular hybrid generators are necessary to inflate the front and side airbags to protect the passengers of the vehicle, but those skilled in the art are available there and at the same time simply produce and store hot gases and reservoirs resulting from the combustion of the pyrotechnic charge. Hybrid generators which carry out all mixing of the cold gas stored in the furnace afterwards are currently not obtained.

It is an object of the present invention to accurately provide such a generator.

Accordingly, the present invention consists of a tubular body having an upper end closed by a pyrotechnic primer device and a lower end hermetically closed, the tubular body having a gas discharge orifice and closed by a septum (S). An internal partition having a central orifice of the primer, the partition forming a combustion and mixing chamber and generating a hot gas, an upper portion comprising a gas exhaust orifice, a pyrotechnic filling, and one or more compressed gases In the hybrid gas generator for partitioning the tubular body into two parts of the lower part forming a storage compartment for receiving the,

The tubular body consists of a single metal tube and includes a support piece fixed to the body between the pyrotechnic filling and the inner partition at the upper portion thereof, without contacting the inner partition or in contact with the gas outlet orifice. A solid movable piston seated against the partition in proximity to the central orifice of the partition and comprising at least one column of cross-section s smaller than the cross-section S, the column having the base at an opposite end to the partition. A hybrid gas generator comprising a solid base having a cross section larger than S for supporting a peripheral lip preventing contact with the central orifice. In general, the support piece is hollow and the peripheral lips will be spaced apart from the central orifice.

A lip around the column to prevent the central orifice from being blocked by a base that can enter the central orifice of the inner partition without blocking the central orifice, and which can achieve the object of the present invention A solid movable piston with an expandable solid base at the rear portion is used. In particular, once the reservoir is opened by the column of the movable piston, the cold gas is discharged from the reservoir through the central orifice portion of the inner partition which is not covered by the column of the piston to enter the combustion and mixing chamber. At the same time, the expandable base of the piston acts as a deflector for hot gases resulting from the combustion of the pyrotechnic charge. This hot gas cannot enter the reservoir, but is mixed with the cold gas to form a gas mixture exiting the generator through the discharge orifice.

According to a first preferred embodiment of the invention, the hollow support piece and the solid movable piston isolate the pyrotechnic filling from the gas exhaust orifice prior to pyrotechnic operation.

This embodiment makes it possible to ensure good protection and preservation of the pyrotechnic charge over time.

According to a second preferred embodiment of the invention, the support piece consists of a hollow ring which is crimped to the body of the generator, the ring having an inner shoulder to have a diameter facing the pyrotechnic live part and a diameter facing the inner partition. Having a central cylindrical recess, wherein d2 is greater than d1, the ring extends facing the inner partition by a hollow cylindrical neck, the inner diameter of which is equal to d2 and the outer diameter of which is smaller than the inner diameter of the tubular body.

In this case, the movable piston consists of, on the one hand, a cylindrical bag of outer diameter, a cylindrical base of outer diameter d3 between d1 and d2, and a cylindrical column of cross section (s) and length (l), on the other hand It consists of a pin of height (h) less than the length (l) surrounding the column and seated on the base of the body, the pin constitutes a peripheral lip.

In this embodiment, the base of the movable piston rests on an inner shoulder that appears to be a support ring, and a bag of pistons whose height is less than the stroke of the piston enters into the central recess of the ring facing the pyrotechnic filling.

In this embodiment, once the pyrotechnic charge is ignited, the hot gas cannot start mixing with the cold gas from the reservoir and start driving the movable piston. This produces a hybrid generator that allows the protective airbag to be initiated using only low temperature gas.

According to a third preferred embodiment of the invention, the pin constitutes a single piece representing the central duct of the section S, the piece being press-fitted onto the column of the piston.

The cylindrical body of the piston is a metal body and the single piece is advantageously made of rigid plastic.

As a result, according to a fourth preferred embodiment of the invention, the tubular body of the generator will consist of a single metal tube. In this case, it is advantageous for the inner partition and its partition wall to be fixed to the metal tube by a single laser welding operation carried out clearly from the outside through this tube.

Thus, the present invention provides a hybrid tubular generator that is simple and inexpensive to assemble. This generator prevents hot gases from entering the reserve of cold gases and at the same time allows the mixing of hot and cold gases. Thus, for a given reservoir chamber volume, it is possible to extrude a larger amount of gas than is stored in a hybrid generator that does not exhibit this safe form but has the same characteristics.

This possibility is increased, prior to pyrotechnic operation, by the column of the movable piston seating against the bulkhead closing the reservoir chamber and acting as a mechanical pillar to improve the resistance to pressure against the bulkhead.

Detailed description of one preferred embodiment of the present invention is described below with reference to FIGS.

1 is an axial cross-sectional view of a hybrid tubular generator according to the invention.

Figures 2 to 4 show the pyrotechnic operation before, during the pyrotechnic operation and during the pyrotechnic operation, respectively, in the region including the support ring, the movable piston and the inner partition of the generator shown in FIG. Cross-section.

5 is a perspective view of the body of the movable piston;

6 is a perspective view of a single piece being press-fitted onto a column of pistons.

FIG. 7 is a partially cut away perspective view illustrating the pyrotechnic primer device of the generator shown in FIG. 1. FIG.

8 is a sectional view of the device shown in FIG. 7;

Explanation of symbols on the main parts of the drawing

1: hybrid gas generator

4: primer device 5: ring

7: hollow neck 8: igniter

9: electrode 11: cap

16: pyrotechnic charging unit

1 shows a hybrid gas generator 1 according to the invention. This generator 1 consists of a tubular body 2 made of steel. The tube 2 has an upper end 3 which is not compartmentalized but in which the metal ring 5 which forms part of the pyrotechnic primer device 4 which is shown in detail in FIGS. 7 and 8 is corrugatedly fixed.

Thus, the primer device 4 is made of a primer carrier 6 having a base 5 in the shape of a hollow ring extending by a hollow neck 7 in which the electropyrotechnic igniter 8 is corrugatedly fixed. The igniter of the electrode 9 is protected by the shutter ring 10. The cylindrical metal cap 11 is secured around the neck 7 and seated on the base 5 via a flare 12 attached to the base 5. At the opposite end to the flare 12, the cap 11 has a precut plane 13 that can be opened under the influence of an increase in pressure.

The igniter 8 has a narrow top 14 which is surrounded by a spring 15 supporting the pyrotechnic charging section 16 in the form of a multi-perforated lobe block. This block comes into contact with the surface 13 and is held at the top by a perforated packing piece that supports the disk 18 with the central orifice 19. Pyrotechnic charging section 16 is a cap 11 which provides a hermetic separation before operation with a block of a composite solid propellant based on ammonium perchlorate and sodium nitride and containing, for example, a silicone binder as described in US Pat. No. 5,610,444. It is advantageous to consist of.

Since the outer diameter of the cap 11 is smaller than the inner diameter of the tube 2, a tubular spacer piece 20 made of plastic is inserted between the cap 11 and the tube 2 to act as a volume replenishment and thus the filling section 16. ) Prevents the cap 11 from bursting sideways.

The tube 2 also has a lower end 21 to which a metal plug 22 with a gas filter orifice 23 is welded. This orifice 23 is hermetically closed by a plug 24 of welding material.

At the bottom of the pyrotechnic primer device 4, the tube 2 has a gas outlet orifice 25, the center of which is assigned to one and the same radial plane perpendicular to the mother plane of the cylindrical tube 2.

At the bottom of this orifice 25, the tube 2 comprises an inner partition 26 having the shape of a flat disk with a circular orifice 27 of circular cross section S. The partition 26 is disposed inside the partition cap 28. Since the partition 26 and the partition cap 28 are made of metal elements, they may be hermetically fixed to the tube 2 by a single laser welding operation.

Thus, the partition 26 closed by the partition wall 28 partitions the interior of the generator 1 into two separate parts:

An upper part comprising a primer device having a pyrotechnic charging part 16 and a gas venting orifice 25, this upper part forming a combustion and mixing chamber 46,

The lower part forming a reservoir 29 containing at least one compressed gas.

Gases used are inert gases such as nitrogen, argon, helium or mixtures of inert gases and oxidizing gases such as air or argon / oxygen mixtures. The use of gas mixtures containing such oxidizing gases is advantageous when the pyrotechnic charge releases the reducing gas.

The tubular body 2 also includes a hollow support piece 30 on top thereof that comes into contact with the surface 13 of the cap 11 of the primer device 4. This hollow support piece 30 is secured to the tube 2 without crimping with the inner partition 26 or by crimping with the gas outlet orifice 25. The support piece 30 comprises a solid movable piston 31 having a column 32 having a cross section smaller than the cross section S of the central orifice 27 produced by the inner partition 26. This column 32 rests against the partition that closes the orifice 27 and thus constitutes a filler that enhances the resistance of the partition to the pressure of the gas contained in the reservoir.

The support piece 30 and the movable piston 31 are described in more detail with reference to FIG. 2, and in the case of the piston 31 also see FIGS. 5 and 6.

The support piece 30 is a metal piece consisting of a hollow cylindrical ring 33 which is brought into contact with the spacer piece 20 and fixed by crimping into the tube 2, the lower plane of the ring 33 being the orifice. At the upper end of the orifice 25 without blocking. The ring 33 has a central cylindrical recess 35 with an inner shoulder 36. Thus, the recess 35 has a diameter d1 facing the pyrotechnic charging section 16 and a different diameter d2 facing the internal partition 26, where d2 is the center of d1 and the partition 26. It is larger than both diameters d of the orifice 27. The hollow ring 33 extends facing the inner partition 26 by a hollow cylindrical neck 37 which is not in contact with the partition 26. The inner diameter of this neck 37 is equal to d2, while the outer diameter is smaller than the inner diameter of the tubular body 2.

On the other hand, the piston 31 consists of a cylindrical metal body 38 having a cylindrical bag of the outer diameter d1 and a central cavity 40, the role of which will be described later in the specification. The body 38 also has a solid cylindrical base 41 having an outer diameter d3 between d1 and d2. Finally, the body 38 has a cylindrical column 32 of cross section s and length l. The body 38 consists of a single piece of metal and the column 38 is obtained by upsetting a metal which initially occupies the volume of the cavity 40.

The piston 31 also consists of a single piece 42 made of a rigid plastic of uniform height h and onto the column 32 of the body 38 to form a piston 31. It has a cylindrical central duct 43 of cross section s which permits 42 to be press fixed. The single piece 42 has three lateral sectors in the form of fins 44. The height h of the single piece 42 and eventually the height h of the pin 44 is less than the length l of the column 32, even in the illustrated embodiment the neck 37 of the support piece 30. Less than)

Also, the maximum diameter size of the single piece 42 is equal to d2.

When the piston 31 is formed, the piece 42 rests on the base 41 of the body 38 and the pins 44 surround the column 32 so as to constitute an outer lip 45 for this column. do.

When the piston 31 is formed and then secured into the support piece 30, the bag 39 of the body 38 enters the top of the recess 35. When this happens, the hollow support piece 30 and the piston 31 hermetically separate the pyrotechnic fillings 16 and the gas outlet orifices 25 contained in the primer device 4.

The generator 1 described is assembled very simply. The tubular body 2 with the orifice 25 is lifted up and the partition 26 enclosed by the partition cap 28 is secured by crimping. Partition 26 and partition cap 28 are then secured to tube 2 by means of a single laser welding operation carried out clearly from the outside through tube 2. The metal plug 22 is then welded onto the lower end 21 of the tube 2. The support piece 30 comprising the piston 31 is then fixed and crimped so that the end of the column 32 comes into contact with the partition cap 28. The spacer piece 20 and the pyrotechnic primer device 4 are then fixed and the tube 2 is crimped onto the ring 5 of the primer device 4. Finally the reservoir 29 is filled with gas through an orifice 23 which is closed by a plug of welding material 24.

The generator, ie the article formed, will be described in more detail with reference to FIGS. 3, 4 and 8.

When a collision is detected that requires the operation of the generator, an electrical signal activates the electropyrotechnic igniter 8, which ignites the pyrotechnic charging section 16, and the combustion gas is transferred to the surface 13 of the cap 11. Let it burst. Thus, as long as the bag 39 is coupled to the narrow portion of the recess 35 disposed above the shoulder 36, the hot gas cannot enter the neck 37 of the support piece 30 and thus the piston 31. It enters into the cavity 40 of the bag and presses it forward. As soon as the bag begins to move forward and shortly, the column 32 guided by the outer lip 45 ruptures the partition 28 and the cold gas contained in the reservoir 29 burns through the central orifice 27. And flows back into the mixing chamber and exits the generator 1 through the orifice 25 without mixing with the hot gas. Therefore, the start of use of the protective airbag is only achieved by using a low temperature gas that does not impair the bending of the airbag near the gas discharge orifice 25. This is a further advantage provided by the preferred embodiment of the present invention.

Under the propulsion of the gas upon combustion of the pyrotechnic charging section 16, the piston 31 continues to move forward but its stroke stops when the outer lip 45 comes into contact with the inner partition 26, so that the piston ( The base 41 of 31 prevents blocking the central orifice 27 of the inner partition 26. At this moment, the length of the bag 39 of the piston 31 is shorter than the stroke of the piston, so that the bag no longer engages in the narrow portion of the recess 35, resulting in the combustion of the pyrotechnic charging section 16. Since hot gas can enter the mixing chamber by flowing around the base 41 of the piston 31, it is mixed with the low temperature gas from the reservoir and discharged from the generator through the discharge orifice 25. The solid base 41 of the piston 31 constitutes a deflector which prevents hot gas from passing directly through the central orifice 27 of the inner partition 26 and actually prevents hot gas from entering the reservoir 29. do. Thus, for the same characteristics, the reservoir 29 used in the generator according to the invention may comprise more gases than the same reservoir used in a conventional hybrid generator which does not prevent hot gas from entering the reservoir.

As described above, the present invention can ensure good protection and integrity of the pyrotechnic charging portion over time, and also has the effect of providing a hybrid gas generator that is simple and inexpensive to assemble.

Claims (7)

It consists of a tubular body (2) having an upper end (3) closed by a pyrotechnic primer device (4) and an airtight closed lower end (21), said tubular body being adapted for the gas discharge orifice (25). And an inner partition 26 having a central orifice 27 of section S closed by a partition 28, the partition forming a combustion and mixing chamber 46 and generating a hot gas. And a hybrid gas partitioning the tubular body into two parts, a gas outlet orifice, an upper portion comprising a pyrotechnic filling portion 16 and a lower portion forming a reservoir 29 containing one or more compressed gases. In the generator 1, The tubular body consists of a single metal tube and at its upper part a support piece fixed to the body, which is not in contact with the inner partition or in contact with the gas outlet orifice between the pyrotechnic filling and the inner partition 26 ( A solid movable consisting of one or more columns 32 of cross-section s comprising a cross section 30 and seating against the bulkhead 28 in proximity to the central orifice 27 of the inner partition 26 and smaller than the cross-section S. A piston (31), said column (32) being larger than S supporting a peripheral lip (45) which prevents the base (41) from contacting the central orifice (27) at an opposite end to the partition. A hybrid gas generator comprising a solid base 41 having a cross section. 2. The hybrid according to claim 1, wherein the support piece (30) and the solid movable piston (31) isolate the pyrotechnic charging portion (16) from the gas discharge orifice (25) prior to the pyrotechnic operation. gas producer. 3. The support piece (30) according to claim 2, wherein the support piece (30) consists of a hollow ring (33) which is crimped to the body (2) of the generator (1), the ring having a diameter facing the pyrotechnic charging section (16). d1) and a central cylindrical recess 35 with an inner shoulder 36 to have a diameter d2 facing the inner partition 26, wherein d2 is greater than d1 and the ring 33 is a hollow cylindrical neck. A hybrid gas generator, characterized by (37) extending facing the inner partition (26), the inner diameter of which is equal to d2 and whose outer diameter is smaller than the inner diameter of the tubular body (2). 4. The movable piston (31) according to claim 3, wherein the movable piston (31) has, on the one hand, a cylindrical bag (39) having an outer diameter (d1), a cylindrical base (41) having an outer diameter (d3) between d1 and d2, and a cross-section (s); Fins 44 of height h smaller than the length l, which consists of a cylindrical column 32 of length l, which, on the other hand, rests on the base 41 of the body and surround the column 32; Comprising of, the pin is a hybrid gas generator, characterized in that the configuration of the peripheral lip (45). 5. The pin (44) according to claim 4, wherein the pin (44) constitutes a single piece (42) representing a cylindrical central duct of cross section (S), wherein the piece is press-fitted onto the column (32) of the cylindrical body (38). Hybrid gas generator, characterized in that. 6. The hybrid gas generator according to claim 5, wherein said cylindrical body (38) is a metal body and said piece (42) is made of rigid plastic. 2. The inner partition 26 and the partition wall 28 are fixed to the tubular body 2 by means of a single laser welding operation which is carried out clearly from the outside through the tubular body 2. Hybrid gas generator.